Stabilizer for lift trucks



Oct. 21, 1952 G, QUAYLE 2,614,643

STABILIZER FOR LIFT TRUCKS v 2 SHEETS-SHEET 1 Filed June 4; 1947 INVENTOR Ai'ToRNEY Oct. 21, 1952 G. F. QUAYLE STABILIZER FOR LIFT TRUCKS 2 SHEETS-SHEET 2 Filed June 4, 1947 INVENTOR ATTORNEY Patented Oct. 21, 1952 UNITED STATES PATENT OFFICE a 'STABILIZEE'FOR LIFT TRUCKS -Geor-ge F. Quayle, Philadelphia, Pa., assignor to The. Yale& Townc Manufacturing Company, Stamford, Conn, a corporation of Connecticut Application: June 4', 1947, Serial No. 752,333

2 Claims. -(Cl. 180-21) Patent No; 2,327,583,.issuedzdugust 27, 1943-. Even more particularly; my invention relates to a type of; truck shown in the Schroeder pending appli cation, Ser. No. 650,479,.fi1ed February 27, 194.6, newv Patent No. 2,548',322,-issued April. 10,, 195.1.

.In trucks. of the: particular class indicatedgitiis customary to mount powerv traction mechanism at. the forward end for actuating a traction or drive wheel, the drive wheel being. adapted-for steering movement by a. steering handle. on which iswplaced switch, mechanism forv controlling the. traction mechanism. Theusual truck extends rearwardly for. quite some distance from'its forward drive wheel, and, at its rearend is supported by: laterally spaced load wheels. In some trucksthese load wheels will, be widely spaced,

but in some trucks the load wheels will be. rather close to one another. When the. truck. is: moving with no load deposited thereon, its center :of gravity is very close to the forward, drive wheel, as most of the weightof the truck-is at the front end. and includes a battery, motor, and lifting mechanism. If.-the truck is steered sharplyto one-sideunder the; conditions just outlined, .it

will, tend to tip; because the center of gravity'is, so-close to the iorwardwheel that the stabilizing;

influence of thetwo spaced rearwheels is not verygreat'. This tendencypof trucks of theparticular. classto tin, especially when the rear of the truck. is. narrow, is well known 'inthe. art and efiorts'have been made. to provide means forstabilizing. such trucks. It is the object of this invention to contribute-to; the arta simple andv effective means for stabilizing a truckof the particular class described.

As one feature of myinvention', I utilizeapair.

orintermediate wheels. secured to the truck, in, laterally spaced position, and intermediate the rear wheels and the forward drive. wheel. The

mine a; ground suhpcrt plane. that distinguishes the broad phases of my invention from: outrigger wheels of the prior: art trucks.

As a further feature of the invention, the-inter mediate pwheelszare preferably normally spaced skilled in the, art will fully, appreciate.

from. the ground plane-determined by. 'thedrive wheel and the load wheels, and one or the other of said intermediate wheels will move against the ground plane when the truck tilts.

As still a further feature of the inventi'on,;.e'ach of the intermediate wheels. has a. rounded outer periphery so that the intermediate wheelsv will roll bodily with the truck and relatively to the, ground plane when the truck tilts relatively "to the ground plane. Of course, this. rolling action will be on an axis transverse to the axis .on whichv the intermediate wheels normally rotate. Those skilled in the art will appreciatefthat because of this rolling action, the intermediate wheels tend better to stabilize the truck, and to prevent its jogging between opposed tilted positions, as, well as its. tipping over on its side. through the particular co-action. of the intermediate wheels with theground plane, there is no tendency for the wheels to dig into the floor on which the truck is driven so that damage to the floor is avoided.

As a still more particular featurebfthe invention, suitable thrust meansare providedfor the intermediate, wheels so that they 'may rotate while rolling bodily with'the truck-against 'thej ground plane transversely to their nornialiaxis; of rotation. i I x A still further, feature of the invention residesin the placing of the intermediatewheels on the.

- elevating platform of the truck so that the wheels will be .ina position to function only when the elevating platform .is -lowered, .therebyignot. hindering the movement of. thetruckwhenjit is loaded and its platform. elevated,,,all, asjfthose I havethus. outlined rather broadly their here.

important features. of my invention. inDIldlsr that the detailed description thereof. tnat ioi-f lows may be better understood,,.'a,n'd-. in Order that my contribution to. the art may be be, er

appreciated. There are, of course, 'ad 'ti'onalf features of my invention thatwwillbe' described hereinafter and which will rormi g u ff the claims appended heretol Those-skilledint e; art will appreciate thatthe, conceptionon hi my disclosureisbasedmay readily 'beiutil ize a; basis, for the designing ofv other "str-uctur u carrying out the several purposes of my; inven-a tion.; It is importanttherefore, thatthe, claims to be granted me shallbe of suflicientbreadthtq; prevent the appropriation of m inventiomby those skilled in the art. a m

. Referringnow to the; drawingsf-li'ign elevation of a. truckembodying mycinventiom Moreover.

Fig. 2 is a view looking downwardly on the truck of Fig. 1. Fig. 3 is an elevation looking from the rear of the truck toward the front thereof. Fig. 4 is an enlarged detail showin the manner in which one of the intermediate wheels is mounted.

Referring now more particularly to the drawings, a truck in which my invention may be embodied is shown having a lifting head it and an elevating platform II. The elevating platform II is pivoted to the lifting head it through upper and lower links designated by reference numerals I 2 and [3 whereby through suitable means the elevating platform may be raised up wardly relatively to the lifting head is. It will be well to indicate at this point, that the particular means for mounting the elevating platform relatively to the lifting head and for lifting the elevating platform relatively to the 1ifting head are well set forth in the application of Charles Schroeder, supra, to which reference may be'made. I shall here merely describe quite generally the construction of the truck, since my invention is independent of the particular construction and is capable of use with any truck of the same general class.

For lifting the elevatin platform, my lifting head It! has mounted thereon a ram assembly l4 adapted to rotate a lifting crank about an axis l6 whereby the part I! of the crank acts against a surface IE! of the elevating platform I i to raise the platform on the links l2 and IS.

The elevating platform I3 is of that type equipped with a pair of spaced legs 19 and iii of the class well known in the art. Each leg I9, 20 has a pair of load wheels 2| adapted for lifting movement through action of a rod 22, the two rods 22 being actuated by movement of the lower links I3, all as those skilled in the art will appreciate, and asis set forth in the Schroeder application.

The forward end of the lifting head Ill supports a suitable traction mechanism 23 having formed as part thereof a traction or drive wheel 24, the entire assembly comprising the drive wheel and traction mechanism being rotatable on the lifting head It! by a steering lever 25. Supported also on the lifting head In for actuating the traction mechanism 23 is a large battery casing 26 within which is mounted a heavy storage battery.

As has already been indicated generally, when the truck illustrated in the drawings is unloaded, its longitudinal center of gravity will be very close to the single drive wheel 24. Because of this relationship of the parts, the opposed load wheels 2! will exert very little stabilizing influ ence, and the truck will have a great tendency to the'truck, and I shall now describe those means.

' 'The forward end of the elevating platform I I is formed with a vertical standard 30, and at each side of the standard 30 as best shown in Figs. 2 and-3, there is supported a short bearing shaft 3 I. Each bearing shaft 3| extends between a plate 32- and a plate '33' of the standard 30, and the 4 shafts 3! are suitably secured against endwise movement relatively to the said plates. Supported for rotation on each bearing shaft 3| is what I call an intermediate wheel 34. These wheels 34 are preferably made of a plastic material that is relatively hard, but I can use aluminum, steel, hard rubber, or any other desirable material, depending on the floor or ground on which the truck will move. Thrust washers 35, 33 are provided at each side of each intermediate wheel 34 as probably best shown in Fig. 4 to accept end thrust under conditions to be presently indicated. It will be noted further that each of the wheels 36 has a rounded periphery, also for an important purpose now to be described.

When the truck of my invention tilts toward the dash and dotted line position shown at the left in Fig. 3, the right hand pair of load wheels 2| shown in Fig. 3 will be raised from the ground and the left intermediate wheel 34 will contact the ground. It will be noted that intermediate wheel 34 will contact the ground not at its edge, as would be the case were the outer periphery thereof conventional; rather, the contact will be at a part of the rounded periphery of the wheel 34, and obviously this means that the floor will not be damaged as would be the case were a sharp edge to strike the floor.

In addition, the rounded peripheral surface of the wheel 34 willallow the entire truck to roll relatively to the ground to an extreme position, after which the truck will roll back to its straight up and down position shown in solid lines in Fig. 3, or even to a tilted position to the right of the said solid line position. During a considerable portion of this rolling movement, the truck will be supported at all times by a part of the intermediate wheel 34, whereas were the wheel 34 even along its periphery instead of rounded, it would merely contact the floor at one edge thereof, then leave the floor, while perhaps the other intermediate wheel contacted the floor with one of its sharp edges. In effect, wewould have a sharp jogging or rocking action instead of the rolling action of my invention.

It will, therefore, be observed that through the utilization of the simple expedient of a rounded wheel, I obtain a rolling motion of my truck when it tends to tilt. I, therefore, obtain a very effective stabilizing action through the utilization of my intermediate wheels 34. It will, of course, be obvious at this time that during this rolling action of the truck bodily with one or the other of the intermediate wheels, the thrust washers accept the thrust against the wheels and facilitate the rotation of the wheels in the event the truck is moving forwardly during the tilting movement thereof.

Because the intermediate wheels are mounted on the elevating platform of the truck, it is, of course, obvious also that the elevating movement of the platform will withdraw the wheels from their lowered position shown best in Fig. 1. Therefore, when the elevating platform is raised,

- which is generallythe condition of the truck if it is loaded and moving, the'intermediate wheels will not be in a position to strike impediments,

as would be the case were'the wheels mounted on the lifting head Hi. v

I believe that the obvious merits of my invention and its considerable contribution to the art, together with its great simplicity, will now be apparent to those skilled in the art.

I now claim:

1. In a-truckofithe'class described, a-lifting contacting portion of said drive wheel exerts a thrust for propelling said truck, laterally spaced load wheels at the rear of said truck coactingwith said forward drive wheel for supporting said truck for normal movement on said wheels, intermediate wheels having metal ground contacting rims, mounting means for said intermediate wheels positioned at laterally spaced points of said truck relatively to said drive wheel and said intermediate wheels being disposed with their entire peripheries behind the nearest portion of the periphery of the drive. wheel and in front of the nearest portion of the peripheries of the load wheels, said mounting means holding said intermediate wheels normally spaced from a ground plane determined by the drive and load wheels, and one of said intermediate wheels contacting the said ground plane when said truck tips relatively to said plane through the lifting of one of.

said load wheels off said ground plane, each of said intermediate wheels having the periphery of its metal ground contacting rim rounded so as to roll bodily with the truck against the ground plane on an axis including the ground contactingportions of said drive wheel and one of said laterally spaced load wheels upon said tipping of the truck.

2. In a truck of the class described, a lifting head, a drive wheel rotatably mounted at the forward end of said lifting head, drive means for rotating said drive wheel whereby the ground contacting portion of said drive wheel exerts a thrust for propelling said truck, laterally spaced load wheels at the rear of said truck coacting with said forward drive wheel for supporting said truck for movement, intermediate wheels having metal ground contacting rims, mounting means for said 4 intermediate wheels positiond at laterally spaced 6 points of said truck relatively to said drive wheel and said intermediate wheels being disposed with their entire peripheries behind the nearest portion of the periphery of the drive wheel and in front of the nearest portion of the peripheries of the load wheels, said mounting means holdings aid intermediate wheels normally spaced from a ground plane determined by the drive and load wheels, one of said intermediate wheels contacting the said ground plane whensaid truck tips relatively to said plane through the lifting of one of said load wheels off said ground plane, each of said intermediate wheels having the periphery of its metal ground contacting rim rounded so as to roll bodily with the truck against the ground plane on an axis including the ground contacting portions of said drive Wheel and one of said laterally spaced load wheels upon said tipping of the truck, and thrust bearings for each of said intermediate wheels for accepting the end thrust against said wheels asthey roll with the truck.

. GEORGE F, QUAYLE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 30 761,564 Walker May 31, 1904 1,588,419 Hickey June 15, 1926 1,763,535 Nuttall June 10, 1930 2,111,983 Massey Mar. 22, 1938 2,121,687 Daus June 21, 1938 35 2,327,583 Frarnhein Aug. 24, 1943 2,417,018 Schroeder Mar. 4, 1947 2,417,395 Framhein Mar. 11, 1947 FOREIGN PATENTS 0 Number Country Date 517,335 France May 4, 1921 

